Color photography



Oct. '6, 1931. J. B. HARRIS, JR 1,825,863

I COLOR PHOTOGRAPHY Filed March 22, 1929 3 n/zawm s #50 60105 Giff/V6510? 8 ZV -W Jgw.

INVENTOR BY mi.

ATTORNEY I Fatented 6, 1931 JOSEPH n. mnms, in. wins menus, camonma colon. rno'roemnr Application filed 1mm; 22, 1929.- serial no. 349,244.

This invention relates to color photography and particularly has reference to the produc tion of a plurality of colored registered images.

V Quite a few processes have been propos for forming a color-photograph, that is, a? photograph which exhibits an image of a subject colored corresponding to the coloring of the subject. This photograph has usually comprised two registered super-imposed images in the same picture space, one of one color and the other of a substantially complementary color. These images have been secured, usually, by printing, develop- 5 ing, and toning one image and then printing, developin and tonin the other images.

A principal object o applicants invention is to provide a process whereby at least two 1 substantially complementary colored supergo imposed images,

obtained by a method which provides for the vformation of the necessary latent image in the positive emulsion before any other treatment thereof. I

In describing the invention in detail and the particular physical product, resulting from the application of the process, selected to illustrate the invention reference is had to the accompanying drawings wherein has so been illustrated a particular physical product resulting'from the practice and application of the invention and wherein like characters of reference designate corresponding parts throughout the several views, and in which Figure l is a schematic representation of a subject; Fig. 2 is a schematic representation of a red color selection negative representative of the reds of the subject, Fig. 1; Fig. 3 is a green color selection negative representation of the greens in the subject, Fig. 1; Fig. 4 is a schematic illustration showing the position of the positive print stock and the negatives during the printing; Fig. 5 is a schematic representation of the print after I the development of one of the images thereline in the same space, may be g Fig; dis a cross-sectional view, of the VI-VI of Fig. 5, illustrating the position in the emulsion of the first developed image; Fig. 7, is a schematic view illustrating the print, Fig. 5, after being toned; Fig.

8 is a schematic view illustrating the print, Fig. 7, after the second development; Fig. 9 is a cross-sectional view on the line IX---IX of Fig. 8 illustrating the position in the emulsionof the second developed image; Flg.

10, is a schematic representation of Fig. 8 after being toned.

Applicant has selected a multi-colored rectangle asa subject by which to illustrate the application of this process. This multiw colored rectangle is illustrated by Fig. 1.

It is divided by two diagonal lines forming four "triangles; One triangle 1, is colored red; another 2, is white; another 3 is colored een; and the fourth, 4, is black.

The first step'in carrying out applicants process is to secure two color selection negatives of the subject, Fig. 1. This is done in the usual and well known manner. The finished red color selection negative desig- 7c nated as a whole by 5, is illustrated by Fig. 2. As the red color selection negative, 2,

is a negative made trom the subject 1 andin accordance with the usual methods the triangle 1 will be'black; the triangle 2 will be black; the triangle 3 will be white; and the triangle 4 will be white. The finished green color selection negative, designated as a whole by 6, isillustrated by 2. In this negative, the triangle 1 will be white; the triangle 2 will be black; the triangle 3 will be black; and the triangle 4 white.

In order to avoid the efiect of alteration in shape or size and especially that alteration known as shrinkage in the positive stock upon which'the photograph is to be made, applicant prefers to form two latent images in the same image space at one and-the same time. In order to do this, applicant posi- W tions the positive stock, designated as a whole by 7 and shown in Fig. 4;, between the red negative 5 and the green negative 6 and uses two printing lights 8 and 9, one positioned on one side of the positive stock and the other positioned of the other side. By such means applicant secures both latent images at one and the same time so that if the negatives 5 and 6 are positioned in registry and the positive stock 7 is held from movement during the printing the latent images formed must be in registry.

Although applicant prefers to form both latent ima es simultaneously, it is of course to be un erstood that such simultaneous printing is not of the essence of this invention because the same result may be secured by successive printings in case they are close together in time and the positive print stock has not been subjected to any operation whichtends in any wise-to cause it to alter its shape or size.

In case either simultaneous or successive printing is employed applicant prefers to use a rint stock having a substantially slow emulslon thereof and refers to have that emulsion :and the colloid bearing the same dyed with a light retarding dye. Such film stock is an article offcommerce and is well known. This stock is generally of a yellowish hue and is generally colored with tartrazin. By using said positive film stock and properly regulating the printing lights 8 and 9, two registered independent images may be simultaneously formed in the emulsion'lO, as shown in Fig. 4:, of the positive print stock 7. One image, that formed from negative 6 would as indicated in dotted lines in Fig. 4 and designated '11 lie substantiall ad acent the transparent, generally celluloi carrier 12; the other image indicated by dotted lines and designated 13 would lie substantially adjacent the face or outside surface of the emulsion 10. These substan- In order to so do applicant prefers to use a developer as follows 18 grams hydroquinone 100 grams -sodium sulphite 4 grams -potassium bromide 18 grams -sodium hydrate 1000 cos water This developer will give rapidly a satisfactory black and white image from the face or outside latent image, so that the print, Fig. 5, after development will appear white in triangle 1; white in triangle 2; black in triangle 3; and black in triangle 4 and the developed image giving the blacks will be substantially at the face of the emulsion, as

shown at 13 in Fig. 6.

The positive stock is next washed and then toned. A suitable toning solution would be as follows:

3 grams -ferric ammonium oxalate 3 grams potassium ferricya'nide 3 grams .citric acid 500 ccs -water The toning bath would be allowed to act for such a time as would give a desired densit of color. The print would then appear as s own in Fig. 7. Too great acidity in this bath is to be avoided.

After a thorough wash the film is placed in a bath as follows:

10 grams .potassium bichromate 10 grams .ammonium bromide 1000 ccs water oper used would be a slow working developer. One designed to bring out the interior image to the fullest extent. A suitable developer would be as follows:

5 grams diamidophenol 60 grams sodium sulphite 5 cos lactic acid 1000 ccs water After the developer is allowed to act the proper time to fully develop the latent image formed adjacent the carrier, that is, in the interior of the emulsion, the film is thoroughly washed and fixed in a thiosulfate bath and then washed. The print will then appear as shown in Fig. 8 in which: triangle 1 will be black; triangle 2 will be white; trian le 3 will be blue; and triangle 4 will contain th blue and black. The position of the black image of Fig. 8 is shown by F i 9 in which 11 indicates the image develope by the second development. This image is adjacent the carrier 12.

The print will then be toned by the use of any suitable toning solution such as:

50 grams sodium citrate 10 grams c11pric sulphate 5 grams potassium ferricyanide 1000 ccs .water After the print is washed and dried it will then appear as shown in Fig. 10 in which: triangle 1 will be red, triangle 2 white; tri- 1. The method of producing a color 'photograph from suitable color selection negatives which consists in first forming latent lmages therefrom within the body of a layer of material containing a light sensitive substance on a transparent carrier, one adjacent outside face of the material, the other adjacent the carrier, then developing and toning with ferric salts the outside image and then resensi- 'tizingl to development, developing and toning t e other image.

2. The method of producing a color photograph from suitable color selection negatives which consists in first forming substantial displaced latent images therefrom within the body of a la%er of material containing a light sensitive su stance on a transparent carrler, then developing and toning the first developed image and then resensitizing to development and developing and toning thesec- 3'. The method of'producing a color photograph from suitable color selection negatives which consists in first forming latent images therefrom within the body of a layer of material containing a light sensitive substance on a transparent carrier, one adjacent the outside face of the material, the other adjacent the carrier, then developing the image adjacent the outside face with a quick acting developer and then toning with ferric salts and then resensitizing to development, and then developing the image ad'acentthe carrier with a slow working developer and then toning the last developed image.

JOSEPH B. HARRIS, JR. 

